The present invention relates to lenses, for example, contact lenses, and to contact lens care systems, having antimicrobial properties. More particularly, the invention relates to lenses and contact lens containers or cases made from antimicrobial materials, for example, polymeric materials which include antimicrobial components.
Contact lenses are often exposed to one or more microorganisms which can result in detrimentally affecting the mammalian eye in which the lens is used. Conventional contact lenses should be periodically disinfected by the user to prevent infection or other deleterious effects on ocular health which may be associated with contact lens wear. For example, there are several different conventional systems and methods which enable the user to disinfect his/her contact lenses between wearing times.
Microbial, e.g., bacterial, contamination of contact lens containers or cases used for contact lens care products is a further significant problem. The contact lens case has been implicated as a factor in microbial keratitis due to the fact that most contact lens disinfection systems are designed to deal with contamination on the contact lens, and not necessarily with contamination existing in the contact lens case. Thus, a disinfected contact lens placed in a contaminated contact lens case may itself become contaminated prior to being placed in the eye. This at least partially negates the beneficial effects of contact lens disinfecting. Contact lens cases are continually exposed to environmental contaminants, as well as to the contact lenses themselves. Such contact lens cases often set up a biofilm which is nutritive and protective of microorganisms.
Chromecek et al U.S. Pat. No. 3,591,329 discloses storing and disinfecting hydrophilic gel contact lenses in a system to disinfect the lens consisting of a receptacle divided into two compartments separated by a permeable partition. In one compartment, the hydrophilic lens is stored under an aqueous liquid, while located in the other compartment is a water swellable polymer containing surface active silver ion exchanged onto the polymer. Silver ions from this polymer dissolve in the surrounding aqueous liquid and penetrate into the lens to kill budding spores on the lens. The silver ions released from the polymer have at least the potential of detrimentally affecting the contact lens in the compartment. Also, because the silver on the polymer is being continually depleted, the silver-containing polymer may be effective for only a relatively short period of time.